Sooner rather than later, if you want to understand Mahayana, you're best served by finding a group that practices Mahayana. This is where the rubber meets the road. This forum can help you find some options there, depending on where you are in the world.

There are also some online classes available. I'm posting the link to this one because I know the people who wrote it and run it: you can go at your own pace and it's free of charge. http://www.tendai.eu/82.html Hopefully people will direct you to some other choices.